Lymphoglandular complexes are important colonic sites for immunoglobulin A induction against Campylobacter jejuni in a swine disease model.

Campylobacter jejuni is a common cause of serious food-borne illness. In an experimental model of human infection, germfree pigs were given C. jejuni, the whipworm Trichuris suis, dual infections with C. jejuni and T. suis, or no infection. In dual-infected pigs, a synergistic effect between C. jejuni and T. suis was observed 27 days after infection, when T. suis fourth-stage larvae were found in the proximal colon. In dual-infected pigs, lymphoglandular complexes (LGCs) in the distal colon were substantially enlarged, and C. jejuni was detected in cells of the follicle-associated epithelium (FAE) and in cells with macrophage morphology within these follicles. In the study reported here, cell types in colonic tissues from these pigs were analyzed by use of immunohistochemical and morphometric analyses for cell surface markers (IgM, IgG, IgA, CD4, CD8, MHC Class II, and macrophage SWC3a). To our knowledge, we provide the first description of cell types in mammalian LGCs, document that they have all elements necessary for antigen processing, and demonstrate the appearance of IgA germinal centers (GC) in LGCs from C. jejuni-infected pigs (single or dual infected). Ileocecal Peyer's patches (ICPP) and mesenteric lymph nodes (MLN) also had IgA GC development if C. jejuni was present, but LGCs had the greatest amount of anti-C. jejuni staining, and appreciable increase in overall follicle size and size and number of GCs committed to IgA production. LGCs are present in humans and other mammals and are important in other enteric infections.